Some U.S. government agencies are using IT systems running Windows 3.1, the decades-old COBOL and Fortran programming languages, or computers from the 1970s.

A backup nuclear control messaging system at the U.S. Department of Defense runs on an IBM Series 1 computer, first introduced in 1976, and uses eight-inch floppy disks, while the Internal Revenue Service's master file of taxpayer data is written in assembly language code that's more than five decades old, according to a new report from the Government Accountability Office.

Some agencies are still running Windows 3.1, first released in 1992, as well as the newer but unsupported Windows XP, Representative Jason Chaffetz, a Utah Republican, noted during a Wednesday hearing on outdated government IT systems.

The government is spending more than US$80 billion a year on IT, and "it largely doesn't work," Chaffetz said during a House of Representatives Oversight and Government Reform Committee hearing. "The federal government is years, and sometimes decades, behind the private sector."

U.S. agencies now spend about spend about 75 percent of their IT budgets maintaining existing or legacy systems, with only about 25 percent going toward procuring new systems, said Dave Powner, director of IT management issues at the GAO.

The GAO told lawmakers that the Department of Veterans Affairs' payroll system and its benefits delivery network is written in COBOL, a programming language dating back to the 1950s, as is the Department of Justice's federal inmate tracking system and the Social Security Administration's retirement benefits system.

Committee members pushed tech officials from three agencies to update their IT systems. Agencies are working to modernize, but in some cases, the old systems still work and are low on the priority lists, the agency representatives said.

For example, the DOD's Strategic Automated Command and Control System for nuclear forces, running on an IBM Series 1, is a "tertiary" system that maintains 99.99 percent uptime, said Terry Halvorsen, CIO for the agency. The system is slated for replacement, but not until year three of a five-year modernization plan, he said.

Budget cuts in recent years have also slowed agencies' ability to update their IT systems, added Terry Milholland, CTO at the IRS. The IRS has about 650 fewer IT workers now than it did in 2011, said Representative Elijah Cummings, a Maryland Democrat.

Republican committee members questioned the impact of recent budget cuts. In the early to mid-2000s, the IRS received significant budget increases, said Representative Mick Mulvaney, a South Carolina Republican.

"When you're still using technology and computer systems from the '70s and the '80s, this is not a problem that started in 2012," he added. "How can you really sit here and tell us this is money?"

Several committee Democrats called on Congress to pass the Information Technology Modernization Act, a bill that would establish a $3.1 billion rotating fund to help agencies update their IT systems. An independent panel would review agency fund requests, and agencies would be required to pay back the money after their projects are complete and they presumably achieve cost savings.

The GAO's Powner also noted agencies could see more cost savings by continuing to consolidate data centers, an effort ongoing in President Barack Obama's administration since 2010. While agencies have closed about 3,100 data centers, another 10,500 remain in operation, he said.

Closing an additional 2,000 data centers, in some cases moving to the cloud, could save $5.4 billion, he said. "We need to definitely get more modern," he said.